My grandma's trick was frozen grated butter but I fought that idea for years.

Had the same thing happen to me last spring with a logo job for a restaurant. Guy paid the deposit, I sent proofs, he went quiet for three weeks, then came back asking for the final files without paying the rest. I held them until he paid but it was two months of chasing him. Switched to the thirds thing after that and honestly it's not as much of a hassle as it sounds. You just bill at three clear points and the client never feels like they're handing over a huge chunk at once. Takes one extra invoice and a short email each time. Worth it if you ask me, because the guy who ghosts after paying half will still ghost on thirds but at least you're only out 25% instead of the whole balance.

Did you test it against a known good zone first, or just trust it out of the box? I grabbed a $40 toner off eBay for a panel swap in an old strip mall, and it found a nicked wire inside the wall that the last guy just taped over. Would've spent half a day pulling new wire if I hadn't checked first. That thing's been in my bag ever since, and the fancy brand name gear sits in the truck lol.